/
write_responsewriter.go
121 lines (104 loc) · 2.91 KB
/
write_responsewriter.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
package http
import (
"bytes"
"context"
"io"
"net/http"
"strconv"
"strings"
"github.com/cloudevents/sdk-go/v2/binding"
"github.com/cloudevents/sdk-go/v2/binding/format"
"github.com/cloudevents/sdk-go/v2/binding/spec"
"github.com/cloudevents/sdk-go/v2/types"
)
// WriteResponseWriter writes out to the the provided httpResponseWriter with the message m.
// Using context you can tweak the encoding processing (more details on binding.Write documentation).
func WriteResponseWriter(ctx context.Context, m binding.Message, status int, rw http.ResponseWriter, transformers ...binding.Transformer) error {
if status < 200 || status >= 600 {
status = http.StatusOK
}
writer := &httpResponseWriter{rw: rw, status: status}
_, err := binding.Write(
ctx,
m,
writer,
writer,
transformers...,
)
return err
}
type httpResponseWriter struct {
rw http.ResponseWriter
status int
body io.Reader
}
func (b *httpResponseWriter) SetStructuredEvent(ctx context.Context, format format.Format, event io.Reader) error {
b.rw.Header().Set(ContentType, format.MediaType())
b.body = event
return b.finalizeWriter()
}
func (b *httpResponseWriter) Start(ctx context.Context) error {
return nil
}
func (b *httpResponseWriter) SetAttribute(attribute spec.Attribute, value interface{}) error {
mapping := attributeHeadersMapping[attribute.Name()]
if value == nil {
delete(b.rw.Header(), mapping)
}
// Http headers, everything is a string!
s, err := types.Format(value)
if err != nil {
return err
}
b.rw.Header()[mapping] = append(b.rw.Header()[mapping], s)
return nil
}
func (b *httpResponseWriter) SetExtension(name string, value interface{}) error {
if value == nil {
delete(b.rw.Header(), extNameToHeaderName(name))
}
// Http headers, everything is a string!
s, err := types.Format(value)
if err != nil {
return err
}
b.rw.Header()[extNameToHeaderName(name)] = []string{s}
return nil
}
func (b *httpResponseWriter) SetData(reader io.Reader) error {
b.body = reader
return nil
}
func (b *httpResponseWriter) finalizeWriter() error {
if b.body != nil {
// Try to figure it out if we have a content-length
contentLength := -1
switch v := b.body.(type) {
case *bytes.Buffer:
contentLength = v.Len()
case *bytes.Reader:
contentLength = v.Len()
case *strings.Reader:
contentLength = v.Len()
}
if contentLength != -1 {
b.rw.Header().Add("Content-length", strconv.Itoa(contentLength))
}
// Finalize the headers.
b.rw.WriteHeader(b.status)
// Write body.
_, err := io.Copy(b.rw, b.body)
if err != nil {
return err
}
} else {
// Finalize the headers.
b.rw.WriteHeader(b.status)
}
return nil
}
func (b *httpResponseWriter) End(ctx context.Context) error {
return b.finalizeWriter()
}
var _ binding.StructuredWriter = (*httpResponseWriter)(nil) // Test it conforms to the interface
var _ binding.BinaryWriter = (*httpResponseWriter)(nil) // Test it conforms to the interface